converted segments_on_target_genome to use a new class SegmentTarget; clarifies how the dictionnary is used

fused the dictionnaries seg_len/seg_size and seg_seq into seg_info that contains both the size and the sequence of the segments.

fixed errors between feature key and feature id; this fixes a bug when a feature is split on several lines int he source gff

added a few functions to the class Feature; replaced the parent/child feature_id attribute by the corresponding class instance

turn feature path list into set to check faster if seg is present, in var detail and aln; ignore case where a segment is twice in a feature path

runtime opti, changed feature_seg_list in dictionnary to check if seg present in list, to compute child features paths and to compute cov/id; much faster on human data, not so much on rice and ecoli data

fix bug when there are several haplotypes and option -ht is used; didnt fix bug when there are several haplotypes but option -ht is absent, todo add a warning

Split the code in several files, fixes some bugs

improved how paths and walks are detected and how bed files are attributed to genomes; fixes bug when a genome name was included in another genome name

bug fix when a segment is present in both orientation in the source features; modified search_segment to find the orientation that corresponds to the current feature

Resolve "add-ci"

Closes #3

See merge request !1

continued code refactoring. removed global variable segments_on_target_genome, sorted functions in several files

added option to not output duplicated features in annotation, only the best occurence is kept. corrected the alignment option, it now doesnt print features that didnt pass the filters.